Packages with reduced bond wave propagation and the methods of forming the same

Abstract

A method includes forming a composite carrier comprising forming a first dielectric layer on a carrier, and forming a plurality of metal pads in the first dielectric layer. The formation of the plurality of metal pads includes performing a planarization process to level first surfaces of the plurality of metal pads and the first dielectric layer. A reconstructed wafer is formed to include a plurality of device dies, and a second dielectric layer on the plurality of device dies. The composite carrier is bonded to the reconstructed wafer, and the plurality of metal pads physically contact the second dielectric layer.

What is claimed is: 
     
         1 . A method comprising:
 forming a first composite carrier comprising:
 forming a first dielectric layer on a carrier; and 
 forming a plurality of metal pads in the first dielectric layer, wherein the forming the plurality of metal pads comprises performing a planarization process to level first surfaces of the plurality of metal pads and the first dielectric layer; 
   forming a reconstructed wafer comprising:
 a plurality of device dies; and 
 a second dielectric layer on the plurality of device dies; and 
   bonding the first composite carrier to the reconstructed wafer, wherein the plurality of metal pads physically contact the second dielectric layer,   wherein at a time of the bonding, the second dielectric layer is a blank layer free from metal features therein, and   wherein the forming the plurality of metal pads comprises:
 performing a first etching process to etch the first dielectric layer and to form a first plurality of openings, until the carrier is exposed; and 
 filling the first plurality of openings with a metallic material, wherein the planarization process is performed on the metallic material.